AbstractMaize is considered a source of carotenoids; however, these compounds are highly unstable, degraded by high temperatures, exposure to light and presence of oxygen. The objective of this work was to evaluate the influence of the moisture and type of drying applied to grains on the level of carotenoids in yellow maize. The experiment was conducted in a completely randomized design (2 × 4 factorial), two levels of initial moisture at the harvest (22 and 19%) and three types of drying (in the sun; in the shade and in a dryer) and control (no drying). The samples of grains after drying with 12% of final moisture were analyzed by concentration of total carotenoids, carotenes (α-carotene + β-carotene), monohydroxilated carotenoids (β-cryptoxanthin), and xanthophylls (lutein + zeaxanthin). Initial moisture, type of drying and the interaction between moisture versus drying influence (p≤0.05) the levels of carotenoids in grains. This is the first report about the drying conditions and harvest’s initial moisture as influence on the profile and content of carotenoids in maize grains. Based on the results, this work suggested that the harvest be carried out preferably when the grains present 22% humidity, with drying in a dryer or in shade for further use or storage.

Ainda que sejam considerados os aspectos de magnitude e significância, o estudo de correlações entre caracteres por si só não garante causa e efeito entre eles. Dessa forma, o objetivo deste trabalho foi desdobrar as correlações fenotípicas em seus efeitos diretos e indiretos, pela análise de trilha, considerando o perfil de carotenoides em genótipos de milho. Foram utilizados dados obtidos do ensaio nacional de cultivares de milho conduzido pela Embrapa Milho e Sorgo, no ano agrícola 2004/2005, com média de 10 genótipos em cinco ambientes. Avaliaram-se os teores de carotenoides totais (CT), α e β-carotenos, luteína, zeaxantina e β-criptoxantina. A xantofila zeaxantina apresenta o maior efeito direto sobre β-caroteno. As altas correlações entre β-caroteno e carotenoides totais e entre β-caroteno e β-criptoxantina são devidas ao efeito indireto, via zeaxantina. A seleção direta de genótipos com altos teores de β-caroteno apresenta-se como a alternativa de maior efetividade, mas se outras frações de carotenoides também forem consideradas, esquemas de seleção simultânea de caracteres, por meio da utilização de índices de seleção, mostram-se mais eficientes na obtenção de genótipos com altos teores de β-caroteno do que a resposta correlacionada.

Although aspects of magnitude and significance are considered, the study of correlations between traits, alone, does not necessarily guarantee a cause and effect relationship between them. Therefore, the objective of this study was to use path analysis to allow the unfolding of correlations in direct and indirect effects, considering the carotenoids profile of maize genotypes. Data was obtained from the national assay of maize cultivars conducted by Embrapa Maize and Sorghum in the 2004/2005 growing season, with means of ten genotypes in five environments. The contents of total carotenoids (CT), alpha and β-carotene, lutein, zeaxanthin and β-criptoxantin were evaluated. Xanthophyll zeaxanthin provided the highest direct effect on β-carotene. The high correlations between β-carotene and total carotenoids and between β-carotene and β-criptoxanthin are due the indirect effect via zeaxanthin. The direct selection of genotypes with high levels of β-carotene appears as a more effective alternative, but if other fractions of carotenoids were also considered, methods of simultaneous selection of characters using selection indices are more efficient in obtaining genotypes with high levels of β-carotene than the correlated response.

O objetivo deste trabalho foi avaliar o efeito da aplicação de herbicidas pós-emergentes no teor de carotenoides em grãos de milho verde. Utilizou-se o delineamento inteiramente casualizado com cinco tratamentos - sem aplicação; foramsulfuron + iodosulfuron-methyl-sodium (40 g ha-1); nicosulfuron (20 g ha-1); mesotrione (120 g ha-1) e tembotrione (100 g ha-1) - e duas repetições. Os grãos foram avaliados para teores de luteína, zeaxantina, betacriptoxantina, alfacaroteno e betacaroteno, carotenoides pró-vitamina A, carotenoides totais e percentuais de luteína, zeaxantina e carotenoides pró-vitamina A. Os herbicidas tembotrione e o nicosulfuron não causaram efeitos deletérios nos teores de carotenoides totais ou nas frações com atividade pró-vitamina A.

The objective of this work was to evaluate the efect of post-emergence herbicide application on carotenoid content in green corn grains. A completely randomized design was used, with five treatments - no application; foramsulfuron + iodosulfuron-methyl-sodium (40 g ha-1); nicosulfuron (20 g ha-1); mesotrione (120 g ha-1) and tembotrione (100 g ha-1) -, and two replicates. The grains were evaluated in terms of lutein, zeaxanthin, beta-cryptoxanthin, alpha-carotene and beta-carotene, pro-vitamin A carotenoids, total carotenoid contents, and percentage of lutein, zeaxanthin and pro-vitamin A carotenoids. Tembotrione and nicosulfuron herbicides did not cause deleterious effects on total carotenoids or fractions with pro-vitamin A activity.

O objetivo deste trabalho foi caracterizar e avaliar a variabilidade quanto ao teor e perfil de carotenoides nos grãos de 134 genótipos de milho (Zea mays), com vistas à utilização em programas de biofortificação. Os materiais foram provenientes dos campos experimentais e do Banco Ativo de Germoplasma da Embrapa Milho e Sorgo, Sete Lagoas, MG. São cultivares e híbridos comerciais, linhagens-elite e outros acessos escolhidos com base na coloração amarelo-alaranjada do endosperma. A quantificação do teor de carotenoides totais, carotenos e xantofilas mono-hidroxilada e di-hidroxilada dos grãos foi realizada por método cromatográfico-espectrofotométrico. As médias encontradas nos grãos foram 22,34µ gg-1 de carotenoides totais, 2,55µ gg-1 de carotenos, 3,86µ gg-1 de xantofilas mono-hidroxiladas e 15,93µ gg-1 de xantofilas di-hidroxiladas. Os genótipos foram agrupados em 18 grupos pelo método de Tocher. O germoplasma da Embrapa possui potencial para ser usado em programas de desenvolvimento de linhagens de milho biofortificadas, quanto ao total de carotenoides pró-vitamina A.

The objective of this work was to characterize 134 maize (Zea mays) genotypes, for carotenoids content and build a genetic profile to facilitate future breeding to increase grain nutritional value (biofortification). Seeds came from experimental fields and from the Banco Ativo de Germoplasma of Embrapa Milho e Sorgo, Sete Lagoas, MG, Brazil. The genotypes were co mmercial hybrids, varieties, and inbred lines developed by the Embrapa biofortification program and other accessions, chosen for their yellow-orange endosperm color. Total grain carotenoids, carotenes, xanthophylls (monohydroxylates and dihydroxylates) were determined by chromatographic-spectrophotometric methods. The detected averages were: 22.34µ gg-1 for total carotenoids, 2.55µ gg-1 for carotenes, 3.86µ gg-1 for monohydroxylated xanthophylls, and 15.93µ gg-1 for dihydroxylated xanthophylls. The genotypes variability was divided into 18 groups by the method of Tocher. The Embrapa germplasm has variability and potential for development of maize lines biofortified for total of provitamin A carotenoids.